There is a semiconductor device configured as one package in which a plurality of semiconductor chips is housed. For example, a plurality of semiconductor chips having different functions are housed in one package. The semiconductor chips having different functions sometimes have different sizes. When the semiconductor chips having different sizes are stacked and packaged, a supporting plate is provided between the semiconductor chips, for example, and some semiconductor chips are supported on the supporting plate.
Each semiconductor chip and the supporting plate in the package are covered with a sealing resin. If the adherence between the front surface of the semiconductor chip and the sealing resin or the adherence between the front surface of the supporting plate and the sealing resin is poor, water enters the interface between the semiconductor chip and the sealing resin or the interface between the supporting plate and the sealing resin. The water entering the interface expands by heat which is applied in a reflowing process at the time of implementation of the semiconductor device, for example. As a result of the water expanding at the interface, a crack may appear in the package. Moreover, expansion of the water at the interface may cause exfoliation of the sealing resin, resulting in a reduction in the humidity resistance of the semiconductor device and poor reliability.